If we want to reach net-zero, it’s vital that we move away from using fossil fuels. One area where we all use it is to heat our homes.
Whether this is by using oil or gas, our heating systems are based on fossil fuels. As part of our journey to live a more sustainable life, we wanted to have a sustainable way to keep our home warm.
The solution is to move to non-fossil fuel-based heating systems. Heat pumps are one such system. They use electricity rather than gas and oil to heat your home and water, which can be produced from renewable sources.
We have installed one a few years ago, and in this article, we share with you what it’s like living with an air source heat pump in the UK.
Does A Heat Pump Work With Any Property?
This was a question we asked ourselves when we first started to consider getting a heat pump. There is an assumption that heat pumps only work in new-builds and won’t work in older properties.
The Energy Saving Trust has said that heat pumps work in any type of UK property, citing a study that involved the installation of 750 heat pumps across different property types.
We live in a detached house that was built in the 1850s, with much more recent extensions. This means that just under half of our house has solid walls, while the rest has cavity walls with cavity insulation.
In an ideal world, you first install insulation before a heat pump. But insulating solid walls is expensive, whether you opt for external or internal insulation. We couldn’t afford to install both insulation and a heat pump.
So we decided on the heat pump. We were nervous, because we were concerned that it might not work. But we can now confidently say that it works great even in our higgledy-piggledy home that was built in different time periods.
If you too live in an older home, you can be assured that it can work in your house too.
Why We Decided To Get A Heat Pump
There were two reasons why we wanted to get a heat pump. First, the environmental impact of our oil boiler. The second was our comfort. Because the old part of our house lost heat very quickly, the way the oil heating worked just didn’t keep us warm.
When the heating was on, it was nice and warm. But about an hour after it went off, the house got really cold. Our bedroom during the night got so freezing cold that we had to put an electric heater on.
During the day, from about 10am onwards it started to get cold, so we had to invest in more electric heaters for our offices, as it just got too cold to work from home comfortably.
Our oil boiler clearly wasn’t able to keep our house warm enough, unless we switched it on about four times a day, increasing our heating costs by a lot, not to speak of our carbon emissions.
We also had an elderly cat at the time, who felt the cold. So we were worried that having such a cold house, especially during the night, could be bad for her.
If this scenario sounds familiar to you, then a heat pump could solve your issues of living in a cold home. With a heat pump, the water temperature in the heaters is much lower, but it’s always on so it keeps the house at a constant temperature.
So we wanted to ensure that we have a warm house all day to be as comfortable as possible. With a heat pump, this should be achievable without having to spend huge amounts of money.
The heat loss calculations that we got done by various installers confirmed that changing to a heat pump would cost the same or less than what we spent with the oil boiler. But we should be nice and warm all day.
What To Consider Before Getting A Heat Pump
Before you get a heat pump installed, there are a few things to consider:
- Type of heat pump – ground source or air source heat pump
- Size of radiators required – with heat pumps, you need bigger radiators
- Are there any grants available? – you might be able to get help with the costs
- The right installer – heat pumps only work well if they are sized and installed properly
There are two types you can choose from: ground source heat pumps and air source heat pumps. Most people opt for the latter, because in order to install a ground source heat pump you need enough land for the underground pipe network.
The main difference between the two types is that the air source system takes heat from the air, whereas the ground source system takes the heat from the ground.
This is the first decision to make, and for us it was an easy one. Firstly, because we weren’t sure if we had enough outside space, secondly, because we weren’t keen on our garden being dug up.
But ground source systems are also more expensive, because the installation process is much more involved, so your budget is likely a factor in this decision.
Because a heat pump operates at lower temperatures, it needs bigger radiators than gas or oil heating systems. This can be achieved by having double or triple radiators, which are thicker, or by getting longer ones.
We have a mix of longer, thinner ones and thicker double and triple ones, depending on the space we have in each room. The size of the radiators will depend on how much heat each room loses.
Costs are a huge factor in most decisions, and installing a heat pump can be quite expensive. The price will depend on how big a heat pump you need, how big your home is, how many of your radiators need to be replaced, and if any pipes need moving.
Our installation cost quite a bit, because we need a fairly big heat pump because of the size of the house, but mostly because the old part loses heat quickly. We also needed pretty much every radiator replacing.
So we were very pleased that we could take advantage of a government grant. The Boiler Upgrade Scheme provided us with a grant of £5,000. This has now been increased to £7,500, which is quite a big help towards the cost.
It’s important to check if there are any grants available, so you can reduce the costs.
There are many heat pump installers out there, but not all are good. Most issues with performance are down to the installation and commissioning, which is done by the installer. (Roy et al., 2010)
The size of the unit needs to be calculated correctly to ensure it works with the property. A unit that is too small won’t manage to heat your home in the coldest temperatures. On the other hand, if it’s too big, it will cycle, which will make it less efficient and more expensive to run.
Cycling means that it keeps switching on and off all the time. A heat pump should be on at all tmes for maximum efficiency.
We would recommend getting more than one installer in to quote and do heat loss calculations to see how they compare. There are two things that are important when choosing an installer:
- MCS certification – this means they will give you an MCS certificate after the installation to prove the design, products used, and installation was done to the highest standards
- Gas Safe registered – if you’re currently using a gas central heating system, you want an installer that is Gas Safe registered
You want an installer who is knowledgeable about heat pumps, so don’t be afraid to ask a lot of questions when they come to quote.
The Installation – How Disruptive Is It?
Before we get to what it’s like living with an air source heat pump in the UK, we need to talk about the installation and what to expect from it. Depending on how big your home is, it can take a few days, especially if many of your radiators need changing.
Our installation took about a week. They had to change 8 out of 12 radiators, with some pipework also needing adjusting because of it. And of course the boiler needed replacing as well, which again, involved changing pipes.
There was a whole team of engineers, consisting of 5 people. Because they had to change so many radiators, they needed access to pretty much every room in the house. This meant that for a these few days we had them all around the house.
Working from home, this was quite disruptive. We also had to make sure that our cat was out of the way and safe. Being a house cat, we were worried she might get out.
We asked the installers to make sure they don’t leave any doors open, with which they happily complied. I kept her with me in my office with the doors closed as much as possible to make sure, though.
Apart from the fact that you will have people in your house for a few days, there is also the noise. For us, working from home, this was an issue at times, especially if you’re trying to have an online meeting.
While the install is going on, you don’t have any heating, as they have to switch it off. As we got our air heat pump installed in July, that wasn’t a problem at all. But it’s something to keep in mind.
The hot water was only off when they changed the boiler, which was for one day. Because we knew in advance, we could make provisions, which was really helpful.
Overall, it wasn’t as bad as we thought it might be. This was probably helped by the team being really nice and thoughtful. They protected our carpets with sheets, took off their shoes, and communicated really well, so we always knew what was going on.
So, yes, heat pump installations are disruptive and can take several days. However, if you have a good team of installers, it’s not that bad.
Commissioning And Calibration Period
After the installation, the installer will commission the heat pump. This means he will come, switch it on, and set it up. This is an important part and needs to be done correctly to ensure the maximum performance of the heat pump.
We had two choices to run ours: weather compensation and inside temperature. With the first one, a temperature curve is set up that dictates what flow temperature will be used depending on the air temperatures outside.
When outside temperatures drop, the flow temperature will increase, pumping more heat into our home. Equally, when it gets warmer outside, the flow temperature is lowered.
Not all heat pumps have this type of setup available. But it’s said to be the most efficient way to run it.
The latter is based on the temperatures in the house. The heat pump will try to keep the house at a given temperature.
The installer recommended that we go with weather compensation, as he thought it would work best for our house.
Because part of our home is very old and loses heat quickly, while others are well insulated and therefore don’t lose heat as quickly, the second option would not keep our house at a nice even temperature.
We went with the installer’s recommendation and he set it up accordingly. Over autumn, winter, and spring, we had to calibrate the settings to make it work for us.
The curve that he set was the one he designed the heat pump to. But he said that we’ll likely find that we are too warm. And he was right. As soon as the weather got colder, the house got a bit too warm.
That’s when we started to adjust the curve to calibrate the system to our needs. I won’t lie, it took us until next summer until we got it right. It’s worth saying though that not everyone will have to do that.
If you live in a more modern home, with cavity wall insulation, and more even heat loss than we have, you probably don’t have to play around for that long.
One thing you should be aware of is that when the hot water cycle is running, the heating will go off. It can take between one and two hours. We had the hot water to come on at noon, so that we could benefit from solar energy, as we also have solar panels.
But we would notice that we would get cold during that time. So to avoid that, we changed it to 4am in the morning, because during the night we wouldn’t notice it. Then in late spring, we change it back to noon, to benefit from our solar panels again, until autumn when we change it again.
This is something we do to be more comfortable and because our property is a bit odd when it comes to heat loss. Most other people probably won’t have the same issue as us.
The good news financially in all this is that as we adjusted the system, we made our heat pump more energy efficient, and brought down the running costs.
Living With An Air Source Heat Pump In The UK In Winter
So what’s it like to live with a heat pump during a UK winter? You might remember that when we had the oil boiler, we were cold during the day and freezing during the night.
Now, we are warm all the time. The house is kept at a fairly even temperature. It’s not perfect, because of the makeup of our home, which means it doesn’t lose heat evenly. But we are so much more comfortable now.
And what about the really cold temperatures? We had prolonged cold snaps, with temperatures not going much above freezing during the day and below freezing during the night. And we were still toasty warm.
One thing we weren’t warned about was that the heat pump, being an outdoor unit, will run defrost cycles on a regular basis during the colder months. This is necessary and can’t be stopped.
During these defrost cycles, no more hot water is pumped through the radiators. We do notice it a bit, but not to the point where we get uncomfortable. And once the defrost cycle is completed, the temperature goes back to normal.
Our heat pump does sometimes over or undershoot. Which means it does a lower or higher flow temperature than it should do according to the curve and the outside temperature.
This can lead to us being a bit too hot or cold. Although it’s more likely to overshoot, and it mostly happens when temperatures outside change quickly. It’s not a big deal, but I thought I’d mention it anyway.
If you’re worried that a heat pump can’t keep you warm during cold weather in the UK, don’t worry, they work very well, giving you that cosy feeling you should have.
We were also a bit worried about the noise, as the heat pump is right next to the wall. And while you can hear it it, especially if it works hard during very cold weather, or a defrost cycle, it’s not super loud.
It’s more like a low hum, which soon becomes a background noise that you hardly notice.
Cost Vs Savings – Is It Worth It Financially?
With upfront costs potentially quite high, most people probably want to know if it’s worth it financially. This question will depend on different factors, like how high the costs are and how much you can save.
Heat pumps are considered to be the most energy-efficient heating technology we currently have. (Gaur et al., 2020) This means that for the amount of energy you put in, you get more heat out of it than with an oil or gas boiler.
And according to research by Scottish Power and WWF, having a heat pump installed could add between 1.7% and 3% to the property value, which equates to between £4,500 and £8,000.
But what about savings? According to the heat loss calculation and heat pump design that has been done by our installer, we were likely to only save a small amount of money compared to using our oil boiler.
However, we are warm all the time. To achieve this with our previous heating system, we would have had to spend quite a bit more money.
Because the estimates in the calculations were conservative, our heat pump runs much more efficiently as suggested. This means we save more money than we initially thought.
Whether the savings alone would pay for the cost of the installation depends on the difference between oil and electricity prices in future.
For people like us, who have older homes that are less energy efficient, and who need bigger air heat pumps as a result, it will be more difficult to make back the costs with savings.
If you have a well-insulated home, your upfront costs will be smaller and you will be able to save more. You probably will be able to recuperate the costs in a few years.
Because we have a heat pump, we were able to get Octopus’ Cosy Tariff, which adjusts the price of electricity according to fluctuations of wholesale prices during the day.
There is a base rate, three periods of cheaper rates, and one period of more expensive rates. The most expensive period is during peak times between 4pm and 7pm. The three cheapest rates are between 10pm and midnight, 4am and 7am, and 1pm and 4pm.
With this rate, you can save even more money on energy bills, because during the night, when it’s normally the coldest during winter and the heat pump needs the most energy, you pay less for your electricity most of the time.
If you can also shift energy-intensive tasks, such as using washing machines, dishwashers and tumble dryers, into the cheaper periods, you save even more. Other energy companies might have similar tariffs, so it’s worth checking this before locking into a new contract.
Using such a tariff will make it much more worthwhile financially than without. Whether it’s worth it for you is for yourself to decide.
And there are ways to reduce your energy bills further, such as solar panels and a battery. Our home already had solar panels when we bought it, but we installed a battery, which can store solar energy so we can use it during peak times.
Of course, this means more costs, but we are amazed at how much money we save on our energy bills thanks to the combination of all three renewable technologies, that we definitely think it’s worth it financially.
And it’s a few steps closer to a sustainable life, and maybe even to net-zero.
So, as you can see, living with an air source heat pump in the UK is very comfortable, and you can save money on your energy bills too. So if you are considering it, I would say go for it if you can afford it, and reduce your carbon footprint. But make sure you get a qualified and knowledgeable installer.
